Patch provided by Andrea Weikert (elubie):

With a few tests I have discovered that when quitting Blender the filelist
in SpaceFile doesn't get free'd.

storage.c:
I have replaced strdup for the relname member in BLI_builddir with BLI_strdup.
and malloc with MEM_mallocN for the string member in BLI_addstrings().

filesel.c:
Of course also had to replace free with MEM_freeN in freefilelist().

In freespacelist (space.c) I added call to freefilelist for the SPACE_FILE
space type.

source/blender/src/space.c

@@ -4317,6 +4317,8 @@ void freespacelist(ListBase *lb)
 			SpaceFile *sfile= (SpaceFile*) sl;
 			if(sfile->libfiledata)	
 				BLO_blendhandle_close(sfile->libfiledata);
+			if(sfile->filelist)
+				freefilelist(sfile);
 		}
 		else if(sl->spacetype==SPACE_BUTS) {
 			SpaceButs *buts= (SpaceButs*) sl;